Alternative Energy or Alternative Oil?: The Search for Unknown Reservoirs

by: Krier James
Date: July 2005

"As an energy source, oil is hard to beat," says Ernest Moniz, a physics professor at Massachusetts Institute of Technology. Lifting sledgehammer every three seconds for ten hours will consume just one fortieth of the energy available in one gallon of gasoline.

"Fossil fuels are extraordinarily good energy sources against any rational comparison," Moniz argues, even after considering that just 10% of the total energy is usually converted into real work. Petroleum is a terrific resource, yet a staggering question remains  how much is left?

The issue may seem unresolved, but it is not unaddressed.

"We are not running out of oil . the Stone Age did not end for a lack of stones,'" Moniz went on to say.

Conventional oil sources are mostly in the Middle East. There are also "unconventional" reservoirs in Canada and South America, which add up to more oil than the amount in Saudi Arabia. Current methods, however, cannot tap these sources effectively. In Canada, petroleum is too viscous to run through a pipeline. Likewise, drilling in Puerto Rico is not economically feasible because of the oil's sprawling distribution in the ground.

Fear of Fast Depletion

Practical limitations and mounting dependence have led to a number of "doomsday" predictions. For instance, David Goodstein at Caltech, offers this forecast:

"Our rate of oil discovery has reached its peak and will never be exceeded; rather, it is certain to decline  perhaps rapidly  forever forward."

These worries are nothing new, however. After World War I, the United States Geological Survey predicted that the country's oil supply would be expended by 1928. President Coolidge created the Federal Oil Conservation Board in 1924, one of many steps that propelled the United States and Europe into the Persian Gulf. In 1956, a geophysicist named Dr. M. King Hubbert proposed a simple model for oil production in the lower 48 states (see Figure 1). Hubbert's idea proved accurate because the land was meticulously surveyed.

Figure 1. The "Hubbert Curve" for the continental U.S. Image Courtesy of Science Magazine.

You can find several websites (see Hubbert Peak of Oil Production) and books purport a similar model for the world's oil supply, but they neglect key assumptions, according to Leonardo Maugeri, an analyst for the Italian energy company Eni Spa. First, a worldwide model would suggest that "the geological structure of our planet is well known and thoroughly explored, so that discovery of unknown oil fields is highly improbable" (from Maugeri's Science Magazine article). Second, Maugeri contends that a bell-shaped curve depends on a large number of random variables. Expressing production as purely random variables is overly simplistic and ignores dynamic technological, economic and political processes that influence discovery in the modern world.

The search for alternatives such as liquid hydrogen has gained attention in the last quarter century, but a cost-effective replacement for gasoline has not yet been discovered. Hydrogen burns cleanly, but lags in delivery convenience and energy density. In addition, its established production methods are not very efficient. The electrolysis of water requires electricity and results in a net energy loss. Alternatively, the reformation of natural gas is more efficient but still requires a fossil fuel.

The future of energy rests much on advanced refinement and alternative energy sources. However, much of the problem may lie in our ability to find new sources of petroleum across the globe.

Sound- and Satellite-aided Discovery

Sound energy has acted as a subterranean probe to find oil for over fifty years. In recent times, large vibrator trucks have taken the place of dynamite, sending massive signals through the Earth. The reflection patterns of the signals reveal underground topography. WesternGeco, a modern seismic surveying company, can assess a 500-square-kilometer area using 65 trucks and 600,000 surface sensors, called geophones. The truck plates are designed to strike the surface at a spectrum of frequencies  the reflected waves can reveal possible oil vacuoles and important details like fracture geometry. The data provides a structural map down to depths in excess of 6000 meters.

But not all landscapes are appropriate for WesternGeco's technique. Good coupling between a surveying truck's plates and the ground is critical for an accurate picture of the underlying geology (see Figure 2). Ground that is particularly hard, soft or uneven will have poor coupling.

Figure 2. Non-uniform contact between the ground and the baseplate results in signal degradation. Source: ESA.

"The mechanical energy generated by a vibrator truck is only useful if it gets converted into elastic energy in the ground," says Andreas Laake, a surveyor for WesternGeco.

Similarly, geophones must have adequate contact with the soil for the reflected elastic waves to be recorded. WesternGeco uses satellites to find adequate coupling sites from three-dimension topographic maps of the Earth's surface.

"Until we started using satellite imagery, we could only guess at the coupling and data quality in advance of an actual survey," Laake says. Other satellite information accounts for topographic variations. "Rises or falls in the landscape delay signal arrival time," so data correction becomes a factor.

WesternGeco also uses satellite-derived thermal infrared (TIR) and short-wave infrared to study the geological formations near the surface (Figure 3). According to Laake, the near-surface level is "where 80% of the data distortion comes from." TIR can detect basalt layers, which behave like "a massive reflector . a shield between the surface and the hydrocarbon reservoirs" (Laake).

WesternGeco has already coordinated successful practice runs in the flat deserts of Algeria and Argentina. Given the scale and operating costs of their expeditions, the company's long-term efficacy is questionable. After all, WesternGeco's customers do not turn a profit "for the amount of hydrocarbons theoretically in the ground, but what they actually recover" (Laake).

Figure 3. Thermal imaging is used to find signal obstructers such as mineral deposits near the surface. Source: ESA.

Laake is confident that new detection methods have the potential to bring sustained production. He says, "the technology we are developing can fully apply to other locations." Furthermore, he believes that WesternGeco's overall focus represents "a means of carrying out seismic survey feasibility studies prior to defining survey programs for our clients, and ensuring enhanced data quality for even the most challenging environments."

Maugeri asks us not to "cry wolf" over shortages; he claims, "some areas are relatively unexplored or have been poorly analyzed."

OPEC countries and corporations that rely on the price of gas are reluctant to invest in large exploration efforts, especially since some oil wells' rate of output increases over time. No one is sure exactly how much left, but according to WesternGeco and Leonardo Maugeri, the search for oil has just begun.